Battery rack improvements.

[Aridom82]

Following fellows forum members feedback i added some changes to my battery rack.
I changed the Bms holder to make use of the M3 threaded holes the Jk bms comes with, now it has more air circulating around it.
I added a mini bracket for the jkbms button on the right
I changed the connector brackets to help the current go equally to both wires in the Jk bms.
I added a bracket to the Dcbreaker holder to fix in place the T-fuse in case it pops so the wire does not come loose.
I will add all of these stl files to the resources so anybody can replicate or modify this project

 

[timselectric]

I'm a little disappointed by your lack of conviction.
If you really think it's necessary to protect the breaker with a fuse.
You should have fully committed to all 4 terminals. lol

 

[robbob2112]

I like it. One concern is if the class T gets hot and the material is PLA it might distort.

One other question - why doesn't anyone use cables instead of rods for compression. Then you could check the tension on all 4 cables (or more) with a tensionmeter and adjust as needed. Simple to always know how much tension things are under?

 

[Aridom82]

I'm a little disappointed by your lack of conviction.
If you really think it's necessary to protect the breaker with a fuse.
You should have fully committed to all 4 terminals. lol

I dont get it. Is not that i am trying to protect the Dc Breaker but the whole battery. I asked in another thread if t-fuse, dcbreaker or both was the best, it came out that t fuse is the best protection but i also want to have the Breaker functionality.

 

[42OhmsPA]

I'm jealous of your printing skills.
Sorry if I asked in your other thread already, what software are you using to design?

 

[Aridom82]

I like it. One concern is if the class T gets hot and the material is PLA it might distort.

One other question - why doesn't anyone use cables instead of rods for compression. Then you could check the tension on all 4 cables (or more) with a tensionmeter and adjust as needed. Simple to always know how much tension things are under?

Yep PLA is not ideal here but ABS is hard to print. I checked the whole thing with a flir at full charge in the morning and i didnt saw anything getting really hot. The whole thing was to see if i could avoid buying the tfuse holder, i am still on it.
Well the cables are ok too i guess i didnt built it that way so i dont know if using cables has any unexpected problems, to check the tension i just simply measure the spring with a caliper. Once is set i just have to check it once in a while to make sure is still ok.

 

[Aridom82]

I'm jealous of your printing skills.
Sorry if I asked in your other thread already, what software are you using to design?

After a long search i decided to take the long road and use Freecad. I use the Realthunder version, is much better. Freecad is not intuitive and it takes a while to get used to it, but is truly free and i think is the right idea. I can only hope it gets developed to the level of other freeware like Gimp or Bender.

About skills when you get used to Freecad you can cad this things in 5 mintues. You just get the shape that gets the function done and then start taking out as much material as possible until it looks right enough for you. After that PLA is very easy to print, i never use anything else if i can avoid it.

 

[timselectric]

I dont get it.

I guess it's a good thing that I don't rely on my comical abilities for a paycheck.

 

[robbob2112]

Yep PLA is not ideal here but ABS is hard to print. I checked the whole thing with a flir at full charge in the morning and i didnt saw anything getting really hot. The whole thing was to see if i could avoid buying the tfuse holder, i am still on it.
Well the cables are ok too i guess i didnt built it that way so i dont know if using cables has any unexpected problems, to check the tension i just simply measure the spring with a caliper. Once is set i just have to check it once in a while to make sure is still ok.

The other feature of a holder is it contains any sparks if the fuse decides to come apart.

When I made an enclosure from rock wool panels to stabilize the temp the ABS became a lot simpler. Just have to vent to outside for the fumes. Makes a nice finish if you mist it with acetone.

 

[Aridom82]

I guess it's a good thing that I don't rely on my comical abilities for a paycheck.

Oops i am sorry, i am too literal of a guy myself

 

[Aridom82]

The other feature of a holder is it contains any sparks if the fuse decides to come apart.

When I made an enclosure from rock wool panels to stabilize the temp the ABS became a lot simpler. Just have to vent to outside for the fumes. Makes a nice finish if you mist it with acetone.

Hmmm, lets 3d print a cover then. Hehehehhe

 

[Zwy]

I like it. One concern is if the class T gets hot and the material is PLA it might distort.

One other question - why doesn't anyone use cables instead of rods for compression. Then you could check the tension on all 4 cables (or more) with a tensionmeter and adjust as needed. Simple to always know how much tension things are under?

Threaded rod can have a hard stop on compression.

Somewhere in my posts I showed how to do it and calculate it using poron, nut on each side of compression plate.

 

[robbob2112]

Hmmm, lets 3d print a cover then. Hehehehhe

Haha, if it goes south and needs a cover you better be printing polycarbonate.

 

[42OhmsPA]

After a long search i decided to take the long road and use Freecad. I use the Realthunder version, is much better. Freecad is not intuitive and it takes a while to get used to it, but is truly free and i think is the right idea. I can only hope it gets developed to the level of other freeware like Gimp or Bender.

About skills when you get used to Freecad you can cad this things in 5 mintues. You just get the shape that gets the function done and then start taking out as much material as possible until it looks right enough for you. After that PLA is very easy to print, i never use anything else if i can avoid it.

Thank you. I'll check out the Realthunder version. I haven't gotten very far with the regular.

 

[Aridom82]

Threaded rod can have a hard stop on compression.

Somewhere in my posts I showed how to do it and calculate it using poron, nut on each side of compression plate.

I thought about it for a while and i decided to put 4 springs capable of holding over 1000 N each. They cost like 7 euros a piece but i think it has come out ok. Still i have not seen barely any expansion of the pack from full to empty cells.

 

[Skypower]

I get the T class for its ability to react faster than the breaker, and the breakers primary function is a DC disconnect. I have the same concerns as others with heat. If the bolt’s tension is any way dependent on the plastic’s tension (threads) or compression strength, heat could soften the plastic and reduce the tension of the bolt.